3 Answers
3

I had this issue after updating to a newer patch version of ruby. Unfortunately the header files gem "debugger-ruby_core_source" was locked in to an earlier version in the Gemfile.lock so it didn't have the required header files.

All you need to do is update that gem by doing:

bundle update debugger-ruby_core_source

You should be able to bundle install afterwards.

If you aren't using bundler then just install the latest version before trying to install debugger: